Fix native union type parameter with false

Author: ondrejmirtes

src/Analyser/MutatingScope.php

@@ -2736,6 +2736,8 @@ public function getFunctionType($type, bool $isNullable, bool $isVariadic): Type
 			return new VoidType();
 		} elseif ($type === 'object') {
 			return new ObjectWithoutClassType();
+		} elseif ($type === 'false') {
+			return new ConstantBooleanType(false);
 		} elseif ($type === 'mixed') {
 			return new MixedType(true);
 		}

tests/PHPStan/Reflection/data/unionTypes.php

@@ -43,3 +43,20 @@ function (): void {
 
 	assertType('NativeUnionTypes\\Bar|NativeUnionTypes\\Foo', $f(1));
 };
+
+class Baz
+{
+
+	public function doFoo(array|false $foo): void
+	{
+		assertType('array|false', $foo);
+		assertNativeType('array|false', $foo);
+		assertType('array|false', $this->doBar());
+	}
+
+	public function doBar(): array|false
+	{
+
+	}
+
+}